The present invention relates to a resin-sealed semiconductor device that incorporates diode modules, thyristor modules, or power transistor modules.
A resin-sealed semiconductor of conventional construction shown in FIGS. 7 and 8 as incorporating a two-set diode module by way of example, two diodes chips D1 and D2 are assembled into a module, and externally drawn terminals 1A, 1K, 2A and 2K are respectively connected to an anode electrode and a cathode electrode of the diode chips and are drawn out therefrom. The diode chips D1 and D2 are solder-mounted on a chip base 5 (a copper plate larger than the diode chip) laminated on a heat-dissipating metal base 3 via an insulation substrate 4, the metal base 3 being disposed within an enclosing case 6 which surrounds the parts. The externally drawn terminals 1K and 2K on the cathode electrodes are formed by being drawn upward and being coupled with the chip base 5, the externally drawn terminals 1A and 2A on the anode electrodes are solder-bonded with the main upper face of the diode chips D1 and D2 via ]-shaped connecting pieces 7, and each externally drawn terminal is drawn to the top surface of the case by passing through an upper lid on the case 6, and are laid in one row in the order 1A, 1K, 2K and 2A from left to right.
The case 6 is filled with a molding resin (epoxy resin for example) to seal the parts, including the diode chips assembled in the modules. The molding resin is injected into the case through a resin-injection hole at the center of the top of the case after the case 6 has been bonded to the metal base 3.
The described conventional module construction has the following handling and assembly drawbacks:
(1) If two-set diodes D1 and D2 assembled in a module are to be connected in parallel, for example, since the externally drawn terminals 1A, 1K, 2K and 2A of each diode chip are arranged along a common line of the case, two types of external connecting pieces 9A and 9K having the complex shape shown in FIG. 9 are required to interconnect the diodes, which results in increasing manufacturing costs.
(2) Because the externally drawn terminals 1A, 1K, 2K and 2A are laid along a common line left to right, all have the same conductor width, and the enclosing case 6 fitted onto these externally drawn terminals has a symmetrical shape, it is possible for the case 6 to accidentally be mounted in a reverse direction when the case 6 is being assembled on the metal base. Moreover, because the enclosing case 6 initially has diode terminal symbol markings on it, the actual externally drawn terminals will not match the terminal symbols if the case is accidentally mounted in a reverse direction.
(3) When filling the enclosing case with resin after the parts have been assembled, the externally drawn terminals laid in the case obstruct the free flow of injected resin. This is an inconvenience in that the amount of resin injected will be insufficient, and the resin-filling work will take more time.
(4) The connecting pieces 7, which are separate parts, are disposed on the anode electrode side of the diode chips, between the diode chips and the externally drawn terminals, in order to absorb stress caused as a result of the difference in the thermal expansion of the mold resin and the externally drawn terminals. This structure increases the number of parts as well as the number of man hours required for soldering, causing an increase in costs.
A primary object of the present invention is to provide a semiconductor device construction that will overcome the described problems of known constructions and which will offer advantages in terms of assembly, handling and manufacturing costs.